Landslide and Rockfall failures Characterization with Object-Based 3D Analysis

2020 ◽  
Author(s):  
Efstratios Karantanellis ◽  
Vassilios Marinos ◽  
Emmanouel Vassilakis
Keyword(s):  
Spatial Information ◽  
Point Clouds ◽  
3D Models ◽  
Vital Role ◽  
3D Analysis ◽  
Rockfall Hazard ◽  
Area Of Interest ◽  
Object Based ◽  
Great Heterogeneity ◽  
Close Range

<p>Geological failures from massive rockfall failures to small landslides of few cubic meters are a major geological hazard in many parts of the world. Based on the latest developments, close-range photogrammetry and individually UAV photogrammetry and Light Detection and Ranging systems have become indispensable tools for geo-experts in order to provide ultra high-resolution 3D models of the failure site. TLS suffers from the fact that is sometimes tricky to capture the holistic area of interest from the ground, while some areas may often be obscured by vegetation or negative inclinations. The science of photogrammetry has long been used to accurately detect and characterize landslide and rockfall failures. Due to the continuously increasing spatial resolution capability of new generation sensors, traditional pixel-based approaches are not capable to cope with the level of detail resulted from those sensors. Mostly, landslides present complex and dynamic geomorphological features with great heterogeneity in their spatial, spectral and contextual properties dependent on the specific failure mechanism. In the current study, an object-based 3D approach for the automated detection of landslide and rockfall hazard is presented based on detailed topographic photogrammetric point clouds and 3D analysis. Recent trends show that close photogrammetry will play a vital role on the geological and engineering geological assessments concerning geo-failures. The results show that object-based approach is closer to human interception due to integration of contextual and semantic, spectral and spatial information rather than translating pixel’s spectral information solely. The current procedure provides a detailed objective quantification of landslide characteristics and automated semantic landslide modelling of the case site.</p>

scholarly journals CULTURAL HERITAGE DOCUMENTATION IN SIS ENVIRONMENT: AN APPLICATION FOR "PORTA SIRENA" IN THE ARCHAEOLOGICAL SITE OF PAESTUM

2017 ◽  
Vol XLII-5/W1 ◽  
pp. 427-432 ◽  
Author(s):  
M. Pepe ◽  
C. Parente
Keyword(s):  
Information System ◽  
Information Systems ◽  
Spatial Information ◽  
Point Clouds ◽  
Archaeological Site ◽  
3D Models ◽  
3D Point Clouds ◽  
Close Range ◽  
And Storage

The Heritage Documentation allows the monitoring, maintenance and conservation by the most recent, efficient investigation techniques and storage of data. A key role in Heritage Documentation is represented by the Geographic Information Systems (GIS) and Spatial Information System (SIS), thanks to the possibility offered by this instrument not only to connect spatial elements (geographical features) to attribute tables, but also manage various information in the form of raster (terrestrial, aerial and satellite imagery), 3D point clouds, 3D models and other vector data. <br><br> The paper describes all the activities that lead to the construction of a SIS, especially in relation to the new survey technologies with particular focus at survey performed by Close Range Photogrammetry (CRP). <br><br> In addition, after explaining the relationships between the different information systems that contribute towards creating of a SIS and the various professions involved, a case study in Paestum area (Italy), showing the efficiency of Spatial Information System (SIS) technology, is discussed.

scholarly journals Monitoring and Computation of the Volumes of Stockpiles of Bulk Material by Means of UAV Photogrammetric Surveying

2019 ◽  
Vol 11 (12) ◽  
pp. 1471 ◽  
Author(s):  
Grazia Tucci ◽  
Antonio Gebbia ◽  
Alessandro Conti ◽  
Lidia Fiorini ◽  
Claudio Lubello
Keyword(s):  
Bulk Material ◽  
Laser Scanner ◽  
Ground Truth ◽  
Point Clouds ◽  
3D Models ◽  
Satellite System ◽  
3D Data ◽  
Current Survey ◽  
Close Range ◽  
Global Navigation Satellite

The monitoring and metric assessment of piles of natural or man-made materials plays a fundamental role in the production and management processes of multiple activities. Over time, the monitoring techniques have undergone an evolution linked to the progress of measure and data processing techniques; starting from classic topography to global navigation satellite system (GNSS) technologies up to the current survey systems like laser scanner and close-range photogrammetry. Last-generation 3D data management software allow for the processing of increasingly truer high-resolution 3D models. This study shows the results of a test for the monitoring and computing of stockpile volumes of material coming from the differentiated waste collection inserted in the recycling chain, performed by means of an unmanned aerial vehicle (UAV) photogrammetric survey and the generation of 3D models starting from point clouds. The test was carried out with two UAV flight sessions, with vertical and oblique camera configurations, and using a terrestrial laser scanner for measuring the ground control points and as ground truth for testing the two survey configurations. The computations of the volumes were carried out using two software and comparisons were made both with reference to the different survey configurations and to the computation software.

scholarly journals COMPARISON OF UAV-ENABLED PHOTOGRAMMETRY-BASED 3D POINT CLOUDS AND INTERPOLATED DSMs OF SLOPING TERRAIN FOR ROCKFALL HAZARD ANALYSIS

2016 ◽  
Vol XLII-2/W2 ◽  
pp. 71-77 ◽  
Author(s):  
J. Manousakis ◽  
D. Zekkos ◽  
F. Saroglou ◽  
M. Clark
Keyword(s):  
Feature Recognition ◽  
Hazard Analysis ◽  
Model Development ◽  
Back Analysis ◽  
Point Clouds ◽  
3D Analysis ◽  
Control Points ◽  
Image Block ◽  
Rockfall Hazard ◽  
3D Point Clouds

UAVs are expected to be particularly valuable to define topography for natural slopes that may be prone to geological hazards, such as landslides or rockfalls. UAV-enabled imagery and aerial mapping can lead to fast and accurate qualitative and quantitative results for photo documentation as well as basemap 3D analysis that can be used for geotechnical stability analyses. In this contribution, the case study of a rockfall near Ponti village that was triggered during the November 17th 2015 M<sub>w</sub> 6.5 earthquake in Lefkada, Greece is presented with a focus on feature recognition and 3D terrain model development for use in rockfall hazard analysis. A significant advantage of the UAV was the ability to identify from aerial views the rockfall trajectory along the terrain, the accuracy of which is crucial to subsequent geotechnical back-analysis. Fast static GPS control points were measured for optimizing internal and external camera parameters and model georeferencing. Emphasis is given on an assessment of the error associated with the basemap when fewer and poorly distributed ground control points are available. Results indicate that spatial distribution and image occurrences of control points throughout the mapped area and image block is essential in order to produce accurate geospatial data with minimum distortions.

scholarly journals CHALLENGES IN FLYING QUADROTOR UNMANNED AERIAL VEHICLE FOR 3D INDOOR RECONSTRUCTION

2017 ◽  
Vol XLII-2/W7 ◽  
pp. 423-430 ◽  
Author(s):  
J. Yan ◽  
N. Grasso ◽  
S. Zlatanova ◽  
R. C. Braggaar ◽  
D. B. Marx
Keyword(s):  
Three Dimensional ◽  
Point Clouds ◽  
3D Models ◽  
Emergency Evacuation ◽  
Vital Role ◽  
Indoor Environments ◽  
3D Tracking ◽  
High Dependency ◽  
Indoor Reconstruction

Three-dimensional modelling plays a vital role in indoor 3D tracking, navigation, guidance and emergency evacuation. Reconstruction of indoor 3D models is still problematic, in part, because indoor spaces provide challenges less-documented than their outdoor counterparts. Challenges include obstacles curtailing image and point cloud capture, restricted accessibility and a wide array of indoor objects, each with unique semantics. Reconstruction of indoor environments can be achieved through a photogrammetric approach, e.g. by using image frames, aligned using recurring corresponding image points (CIP) to build coloured point clouds. Our experiments were conducted by flying a QUAV in three indoor environments and later reconstructing 3D models which were analysed under different conditions. Point clouds and meshes were created using Agisoft PhotoScan Professional. We concentrated on flight paths from two vantage points: 1) safety and security while flying indoors and 2) data collection needed for reconstruction of 3D models. We surmised that the main challenges in providing safe flight paths are related to the physical configuration of indoor environments, privacy issues, the presence of people and light conditions. We observed that the quality of recorded video used for 3D reconstruction has a high dependency on surface materials, wall textures and object types being reconstructed. Our results show that 3D indoor reconstruction predicated on video capture using a QUAV is indeed feasible, but close attention should be paid to flight paths and conditions ultimately influencing the quality of 3D models. Moreover, it should be decided in advance which objects need to be reconstructed, e.g. bare rooms or detailed furniture.

scholarly journals THE 3D SURVEY OF THE ROMAN BRIDGE OF SAN LORENZO IN PADOVA (ITALY): A COMPARISON BETWEEN SFM AND TLS METHODOLOGIES APPLIED TO THE ARCH STRUCTURE

2019 ◽  
Vol XLII-2/W15 ◽  
pp. 255-262
Author(s):  
F. Carraro ◽  
M. Monego ◽  
C. Callegaro ◽  
A. Mazzariol ◽  
M. Perticarini ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Point Clouds ◽  
3D Models ◽  
San Lorenzo ◽  
Close Range ◽  
3D Photogrammetry ◽  
Survey Methodologies ◽  
Peculiar Case

<p><strong>Abstract.</strong> 3D survey methodologies are widely applied to the Cultural Heritage, employing both TLS and close-range photogrammetry with SfM techniques. Laser scanning produces models with high metric reliability and accuracy, whereas the main quality of the 3D photogrammetry is the result in term of photorealistic representation. Many studies have been conducted about the comparison and the integration of these different approaches and the aim of this paper is to contribute with a peculiar case study: the underground Roman bridge of San Lorenzo in Padova (Italy). The investigation regards the resulting point clouds of the intrados (or inner curve) of the central arch, comparing them and providing graphical and analytical outputs. The proposed workflow has the purpose to be a simple but valid tool to detect and evaluate geometrical differences, their significativity and the reliability of the 3D models.</p>

scholarly journals 3D HAZARD ANALYSIS AND OBJECT-BASED CHARACTERIZATION OF LANDSLIDE MOTION MECHANISM USING UAV IMAGERY

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 425-430 ◽  
Author(s):  
E. Karantanellis ◽  
V. Marinos ◽  
E. Vassilakis
Keyword(s):  
Surface Morphology ◽  
Road Network ◽  
Laser Scanning ◽  
Complex Surface ◽  
Point Clouds ◽  
High Mountain ◽  
Semantic Classification ◽  
Rockfall Hazard ◽  
3D Point Clouds ◽  
Object Based

<p><strong>Abstract.</strong> Late years, innovative close-range remote sensing technology such as Unmanned Aerial Vehicle (UAV) photogrammetry and Terrestrial Laser Scanning (TLS) are widely applied in the field of geoscience due to their efficiency in collecting data about surface morphology. Their main advantage stands on the fact that conventional methods are mainly collecting point measurements such as compass measurements of bedding and fracture orientation solely from accessible areas. The current research aims to demonstrate the applicability of UAVs in managing landslide and rockfall hazard in mountainous environments during emergency situations using object-based approach. Specifically, a detailed UAV survey took place in a test site namely as Proussos, one of the most visited and famous Monasteries in the territory of Evritania prefecture, in central Greece. An unstable steep slope across the sole road network results in continuous failures and road cuts after heavy rainfall events. Structure from Motion (SfM) photogrammetry is used to provide detailed 3D point clouds describing the surface morphology of landslide objects. The latter resulted from an object-based classification approach of the photogrammetric point cloud products into homogeneous and spatially connected elements. In specific, a knowledge-based ruleset has been developed in accordance with the local morphometric parameters. Orthomosaic and DSM were segmented in meaningful objects based on a number of geometrical and contextual properties and classified as a landslide object (scarp, depletion zone, accumulation zone). The resulted models were used to detect and characterize 3D landslide features and provide a hazard assessment in respect to the road network. Moreover, a detailed assessment of the identified failure mechanism has been provided. The proposed study presents the effectiveness and efficiency of UAV platforms to acquire accurate photogrammetric datasets from high-mountain environments and complex surface topographies and provide a holistic object-based framework to characterize the failure site based on semantic classification of the landslide objects.</p>

scholarly journals Obstacle-Aware Indoor Pathfinding Using Point Clouds

2019 ◽  
Vol 8 (5) ◽  
pp. 233 ◽  
Author(s):  
Lucía Díaz-Vilariño ◽  
Pawel Boguslawski ◽  
Kourosh Khoshelham ◽  
Henrique Lorenzo
Keyword(s):  
Spatial Data ◽  
Spatial Information ◽  
Three Dimensional ◽  
Point Clouds ◽  
3D Models ◽  
Indoor Environments ◽  
Aged People ◽  
Emergency Assistance ◽  
Indoor Scenes ◽  
Mobility Skills

With the rise of urban population, updated spatial information of indoor environments is needed in a growing number of applications. Navigational assistance for disabled or aged people, guidance for robots, augmented reality for gaming, and tourism or training emergency assistance units are just a few examples of the emerging applications requiring real three-dimensional (3D) spatial data of indoor scenes. This work proposes the use of point clouds for obstacle-aware indoor pathfinding. Point clouds are firstly used for reconstructing semantically rich 3D models of building structural elements in order to extract initial navigational information. Potential obstacles to navigation are classified in the point cloud and directly used to correct the path according to the mobility skills of different users. The methodology is tested in several real case studies for wheelchair and ordinary users. Experiments show that, after several iterations, paths are readapted to avoid obstacles.

scholarly journals THE POSSIBILITIES TO SUPPORT ZB GIS DATABASE UPDATE USING OBJECT-BASED IMAGE ANALYSIS IN ECOGNITION DEVELOPER SOFTWARE

2014 ◽  
Vol 40 (3) ◽  
pp. 122-132
Author(s):  
Tatiana Harcinikova ◽  
Hana Stankova
Keyword(s):  
Image Analysis ◽  
Change Detection ◽  
Agricultural Landscape ◽  
Spatial Information ◽  
Object Based Image Analysis ◽  
Information Classification ◽  
Area Of Interest ◽  
Object Based ◽  
Mountainous Landscape ◽  
Stored Information

The process of updating a spatial database is a necessary part of database management in order to keep the stored information of an acceptable quality. The first step of database update requires change detection. Many methods have been suggested to detect changes, mostly pixel-based. Recently, with the spread of very high resolution images and object-based image analysis, object-based methods were developed, too. This article presents object-based change detection method for update of the vector database ZB GIS, that is a geometric base of the Slovak National infrastructure of spatial information, using orthophoto of the area of interest. The method stages include the following: segmentation of orthophoto using the geometry of database objects and further according to spectral and spatial information, classification according to ZB GISR, defining reclassification rules between two classes. The proposed method was tested in two localities – Malženice (agricultural landscape) and Chopok-Jasna (mountainous landscape) reaching the overall accuracy of classification 87.12% and 84.55%, respectively. The main limitation of the method is that it can be applied only for polygonal objects.

scholarly journals Digital 3D models of theropods for approaching body-mass distribution and volume

2021 ◽  
Author(s):  
Matías Reolid ◽  
Francisco J. Cardenal ◽  
Jesús Reolid
Keyword(s):  
Body Length ◽  
Heat Dissipation ◽  
Volume Ratio ◽  
3D Models ◽  
The Body ◽  
3D Analysis ◽  
Skull Length ◽  
Knowing That ◽  
Fossil Bones ◽  
Primitive Forms

AbstractThe aim of this work is to obtain diverse morphometric data from digitized 3D models of scientifically accurate palaeoreconstructions of theropods from eight representative families. The analysed polyvinyl chloride (PVC) models belong to the genera Coelophysis, Dilophosaurus, Ceratosaurus, Allosaurus, Baryonyx, Carnotaurus, Giganotosaurus, and Tyrannosaurus. The scanned 3D models were scaled considering different body-size estimations of the literature. The 3D analysis of these genera provides information on the skull length and body length that allows for recognition of major evolutionary trends. The skull length/body length in the studied genera increases according with the size of the body from the smallest Coelophysis with a ratio of 0.093 to ratios of 0.119–0.120 for Tyrannosaurus and Giganotosaurus, the largest study theropods. The study of photogrammetric 3D models also provides morphometric information that cannot be obtained from the study of bones alone, but knowing that all reconstructions begin from the fossil bones, such as the surface/volume ratio (S/V). For the studied theropod genera surface/volume ratio ranges from 35.21 for Coelophysis to 5.55 for Tyrannosaurus. This parameter, closely related to the heat dissipation, help in the characterization of the metabolism of extinct taxa. Accordingly, slender primitive forms of the Early Jurassic (i.e. Coelophysis and Dilophosaurus) had relatively smaller skulls and higher mass-specific metabolic rates than the robust large theropods of the Cretaceous (i.e. Giganotosaurus and Tyrannosaurus). This work presents a technique that, when applied to proper dinosaur models, provides extent and accurate data that may help in diverse study areas within the dinosaur palaeontology and palaeobiology.

scholarly journals Accuracy of cup placement in total hip arthroplasty by means of a mechanical positioning device: a comprehensive cadaveric 3d analysis of 16 specimens

2019 ◽  
pp. 112070001987482
Author(s):  
Arthur J Kievit ◽  
Johannes G G Dobbe ◽  
Wouter H Mallee ◽  
Leendert Blankevoort ◽  
Geert J Streekstra ◽  
...  
Keyword(s):  
3D Models ◽  
Safe Zone ◽  
3D Analysis ◽  
Anterior Pelvic Plane ◽  
Mechanical Device ◽  
Acetabular Cup ◽  
Anteversion Angle ◽  
Positioning Device ◽  
The Mean ◽  
Safe Zones

Introduction: We tested whether a mechanical device (such as Hipsecure) to pinpoint the anterior pelvic plane (APP) as a guide can improve acetabular cup placement. To assess accuracy we asked: (1) is the APP an effective guide to position acetabular cup placement within acceptable ° of divergence from the optimal 40° inclination and 15° anteversion; (2) could a mechanical device increase the number of acetabular cup placements within Lewinnek’s safe zone (i.e. inclination 30° to 50°; anteversion 5° to 25°)? Methods: 16 cadaveric specimens were used to assess the 3D surgical success of using a mechanical device APP to guide acetabular cup placement along the APP. We used the Hipsecure mechanical device to implant acetabular cups at 40° inclination and 15° anteversion. Subequently, all cadaveric specimens with implants were scanned with a CT and 3D models were created of the pelvis and acetabular cups to assess the outcome in terms of Lewinnek’s safe zones. Results: The mean inclination of the 16 implants was 40.6° (95% CI, 37.7–43.4) and the mean anteversion angle was 13.4° (95% CI, 10.7–16.1). All 16 cup placements were within Lewinnek’s safe zone for inclination (between 30° and 50°) and all but 2 were within Lewinnek’s safe zone for anteversion (between 5° and 25°). Conclusion: In cadaveric specimens, the use of a mechanical device and the APP as a guide for acetabular cup placement resulted in good positioning with respect to both of Lewinnek’s safe zones.

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